Contact assembly clamp and base



July 23, 1968 H. H. KOBRYNER CONTACT ASSEMBLY CLAMP AND BASE Filed July 6, 1966 e m m w 4 W i 2 United States Patent 3,394,340 CONTACT ASSEMBLY CLAMP AND BASE Herman H. Kobryner, Forest Hills, N.Y., assignor to Murray Manufacturing Corporation, Brooklyn, N.Y., a corporation of New York Filed July 6, 1966, Ser. No. 563,282 8 Claims. (Cl. 339-217) ABSTRACT OF THE DISCLOSURE The invention contemplates so initially forming a base block for electrical contacts that it inherently lends itself to later installation of added contacts, without disruption of service. Contacts for base blocks of the character indicated must occasionally be added to watt-hour meter mounts, switch boxes, fuse boxes and the like, and the invention is applicable to all these situations. The added-contact assembly is unit-handling, inherently anchors itself to the base, and inherently ruggedly supports upstanding jaws or other elements relied upon for the added contact.

My invention relates to the mounting of electrical contacts, as in watt-hour meter mounts, switch boxes, fuse boxes, and the like.

In certain situations, it becomes necessary to add an electrical contact on an installed and wired device of the character indicated, and this must be done without distrubing the wiring and without removing the base on which it has to be mounted. If the base material is unthread-able, as for example porcelain, and if it has not been provided with suitable mountings, as for example captive nuts under holes, or pre-assembled studs, in anticipation of future additions, it is impossible with available parts to mount the needed additional contact without reaching to the underside of the base for insertion of a screw or nut. And, of course, any such access would mean disruption of service.

It is, accordingly, an object of the invention to provide an improved structure whereby an additional contact or contacts may be added to a service installation of the character indicated, without any disruption of service.

A specific object is to provide a unit-handling addedcontact assembly of elemental simplicity from the points of view of both fabrication and ease of installation, and inherently capable of installation from the front of the base.

Other objects and various further features of novelty and invention will be pointed out to those skilled in the art from a reading of the following specification in conjunction with the accompanying drawings. In said drawings, which show, for illustrative purposes only, a preferred form of the invention:

FIG. 1 is an enlarged view in perspective showing a contact assembly of the invention about to be mounted in a suitably formed insulating base of the invention;

FIG. 2 is a sectional view in the plane 22 of FIG. 1;

FIG. 3 is a view similar to FIG. 2., but showing the parts in the process of assembly to each other; and

FIG. 4 is a view similar to FIG. 3 showing the parts secured in assembled position.

Briefly stated, the invention contemplates so initially forming a base block for electrical contacts that it inherently lends itself to later installation of added contacts, without disruption of service. Contacts for base blocks of the character indicated must occasionally be added to watt-hour meter mounts, switch boxes, fuse boxes and the like, and the invention is applicable to all these situations. The added-contact assembly is unithandling, inherently anchors itself to the base, and inherently ruggedly supports upstanding jaws or other elements relied upon for the added contact.

Referring to the drawings, the invention is shown in application to an insulating base 10 which may be of porcelain and which forms part of a watt-hour meter mount, switch box, fuse box or the like. For purposes of explaning the invention, it is not necessary to show the contacts of the watt-hour meter mount, switch box, fuse box or the like, and therefore only a fragment of the base 10 is shown in the drawings. It sufiices to explain that the base 10 is secured by means 11 to a panel or bottom 12 of the sheet-metal structure forming the mount or box.

The body of the base 10 may be said to include a lower body portion 13 resting securely on the panel 12 and intended to remain in secured relation thereto. An upper body portion 14 includes an edge part or side 15 laterally offset from the lower body portion so as to overhang a part of the mounting panel 12 in spaced relation therewith.

In anticipation of future requirements for the addition of contacts in a given installation comprising elements 10-11-12, the body 10 is initially formed with suitable grooves and anchoring recesses to receive, locate and permit later front assembly of a unit-handling contact assembly 16. In the form shown, These grooves comprise essentially an elongated horizontal groove having spaced side walls as at 17, and a bottom 18 Within the central part 19 of which is provided a further groove which renders the central region of the horizontal groove greater in depth, and of limited lesser width, than at the outer limits (i.e., between side walls 17).

Communicating with the horizontal grooves 171819 is a vertical groove at the outer edge 15. This vertical groove is shown to have side Walls, as at 2th, continuous with the walls 17 and a flat seating bottom 21 corresponding to the bottom 18 of the horizontal groove. A further recess at 22 in the vertical groove renders the central region thereof of greater depth, and of limited lesser width, than between side walls 20.

Additionally, limited recess 23 is provided on the underside of the. offset 15 for anchoring purposes. This recess 23 is located inwardly of the bottom of the vertical groove and is located below and in register with the horizontal groove; as shown, it is immediately adjacent the inner side wall of the lower body portion 13.

The structural detail thus far described for the base 10 is formed as molded contouring of the base It and may have no functional relation to the remainder of the assembly into which the base block 10 is initially inco rporated. It thus may be only at a later date, when the need for an additional contact arises, that this special contouring has utility; and at such time, the additional contact is incorporated into the structure without any interruption of service or loosening or removal of the base 10 from its mounting panel 12.

The contact assembly 16 to be added to base 10 is shown'to comprise a generally I-shaped metal strip 25 having a longer arm 26 and a shorter arm 27 integrally connected to each other by a bent portion, shown as straight elements 28 joined to each other and to the arms 26-27 at locally weakened areas caused by apertures 29. The outer extremity of the shorter leg 27 is provided with an upstanding anchoring lug 30 for reception in the recess 23. Clamp means in the form of a bolt 31 has a shank passing loosely through clearance hole 32 in the longer leg 26 and threadedly engaging a smaller tapped hole 33 in the shorter leg 27.

The contact structure 34 provided by assembly 16 is shown as a pair of spring jaws of the type used in watthour meter mounts, fuse boxes, switch boxes and the like. These jaws may be formed integral with the sheet metal of the J-structure 35, but in the form shown jaws 34 are a separate generally U-shaped formation bolted to the J-structure 25. Thus, the jaws 34 may be said to comprise upstanding arms 3536 extending in spaced relation from a base 37 and having re-entrant ends 38 in resilient wiping contact with each other. Preferably, a tongue 39 is bent up from the body of the longer leg 26 so that it may extend over the jaw base 37 and permit securing by a bolt 40 passing loosely through an aperture in the jaw base 37 and threaded into the tongue 39.

The offset of the tongue 39 with respect to the rest of the longer leg 26 is preferably such that the underside of the leg 26 is substantially in the same horizontal plane as the underside of the jaw base 37, for firm, continuous seating support on the surface 18 of the mounting block 10. Similarly, the contouring of the center groove portion 19 is preferably such as to receive and support the contouring of the head of bolt 40.

When adding the contact assembly 16 to an existing meter, fuse or switch installation which includes the base 10, the contact assembly 16 is manipulated laterally in the direction of the arrow of FIG. 2 so as to nest the longer arm and jaw 2634 within the contours of the horizontal groove 1748-19 upon sufiicient insertion, as into the relation of parts shown in FIG. 3. The anchoring lug 30 registers with the anchoring recess 23 and the longer arm, complete with secured jaw 34, is uniformly supported along the length of the horizontal groove. At the same time, the shank of bolt 31 is received within the central recess 22 of the vertical groove system. All that then needs to be done is to secure the bolt 31, thus applying clamping force between the spaced arms of the J-structure. The added wiring that is involved with installation of the contact assembly 16 may first be looped under the head of the bolt 31 so that it too is anchored in place. In the process of anchoring the contact assembly 16 to the base during the application of clamping force by bolt 31, the bends at 28 become more accentuated (through the partial collapse that accompanies deformation) and at the same time offer sufficient stiff resistance to assure a strong clamp of both legs 26-27 in position. The J fitting is permanently deformed after the initial tightening. Thus, the bolt may then be loosened and the jaw assembly will not fall out. Alternatively, the wire may be placed under the head of the bolt, after the fitting has been deformed, and the bolt loosened to accommodate the wire.

It -will be seen that I have described an improved contact assembly lending itself inherently to installation without interruption of service. For example, arrangement has application in watt-hour meter mounts, as Where a fifth jaw must be installed in the field on an existing wired 4-jaw device. It also has application in situations where an additional pole is needed on a multi-pole switch, to cooperate with an additional break-jaw and hingeblade assembly. Alternatively, my structure lends itself to providing additional contacts in a bank of cartridge fuses where empty places may have been left to accept additional clips.

While I have described the invention in detail for the preferred form shown, it will be understood that modifications may be made without departing from the scope of the invention as defined in the claims which follow.

I claim:

1. In combination, a base of insulating material for supporting electrical terminal elements, said base including a lower body portion adapted for mounting on a mounting panel, said base also including an upper body portion an edge part of which is laterally offset from the adjacent edge of the lower body portion so as to overhang a part of the mounting panel in spaced relation therewith, said upper body portion having a horizontal groove therein extending across the offset of said edge part and generally transverse to the edge thereof, said upper body portion having a vertical groove in said edge part communicating with the horizontal groove, and the underside of said offset edge part having an upwardly extending anchoring recess spaced inwardly from the vertical groove and beneath the horizontal groove; and a front-mounted unit-handling electrical terminal element including a gen erally J-shaped deformable bent metal strip having a longer leg and a shorter leg, said strip being of width received and located by the horizontal and vertical grooves with said longer leg in the horizontal groove, said shorter leg being formed at the end with an upwardly extending anchoring lug for reception in the anchoring recess, said strip being initially formed with a spacing between opposed parts of said legs such that said strip may be laterally inserted into horizontal-groove location of said longer leg, with said anchoring lug poised for entry into the anchoring recess upon strip deformation to displace said legs toward each other, clamp means coaeting between opposed parts of said legs and received within the vertical groove and including an upwardly exposed adjustable element for tightening said longer leg in located position within the horizontal groove by a collapsing deformation of the bend of said strip to displace said legs toward each other and thereby cause said lug to locate in the anchoring recess, and an upwardly exposed external electrical contact element on said longer leg.

2. The combination of claim 1, in which said contact element comprises an upwardly extending pair of contact aws.

3. The combination of claim 1, in which said contact element comprises a pair of jaws formed from a single metal strip of generally U-shape, characterized by a base secured to said longer arm and by upstanding opposed legs with reentrant ends, folded into resiliently loaded mutual wiping contact.

4. The combination of claim 1, in which said clamp means includes a bolt loosely through an aperture in said longer leg and threaded to said shorter leg.

5. The combination of claim 1, in which the vertical groove has a central region of greater depth and lesser width than at the outer limit thereof, and in which said clamp means includes a headed bolt with a shank loosely passing through an aperture in said longer leg and threaded in said shorter leg, said shank being received and located in the central region of the vertical groove.

6. The combination of claim 1, in which the horizontal groove has a central region of greater depth and lesser width than at the outer limit thereof, and in which said contact element com rises a separate part bolted to said longer leg, the head of the bolt being received and located by the central region of the horizontal groove.

7. The combination of claim 3, in which said longer arm extends within the space between said jaws and over the base thereof, said jaws and longer arm being secured by a bolt passing through an aperture in said base and threaded into said longer arm.

8. The combination of claim 3, in which said longer arm extends within the space between said jaws and over the base thereof, said jaws and longer arm being secured by a passing through an aperture in said jaw base and threaded into said longer arm, the bottom of the horizontal groove being centrally recessed to receive the bolt head while permitting the jaw base to seat in the horizontal groove around the bolt recess thereof.

References Cited UNITED STATES PATENTS 516,853 3/1894 Turner 3392.66 1,821,575 9/1931 Potter 339245 2,720,636 10/1955 McKinley 339 250 2,865,013 12/1958 Kazanowski 339-219 3,148,930 9/1964 Healy 339219 MARVIN A. CHAMPTON, Prilmu'y Examiner.

R. S. STROBEL, Assistant Era/ulnar. 

